$62.4M to strengthen levees

Improves protection for Lathrop, SW Manteca

The chances of flooding in Lathrop and southwest Manteca will be reduced significantly thanks to $62.4 million in state bond money awarded this week to Reclamation District 17.

The work will maintain protection against a 100-year flood event and go a long way towards 200-year protection. The 100-year and 200-year monikers are a bit misleading as they are described as flooding that has a chance of happening every 100 years based on natural conditions. As more valley soil has been paved or built on run-off has increased significantly reducing the times between major flooding.

The money is being wedded with $1 million being raised from a $37 parcel tax assessment over five years that a majority of 4,000 home owners in Lathrop, Weston Ranch, and the extreme southwest edge of Manteca voted to put in place. The parcel tax made it possible to secure the state bond money.

The parcel tax also allowed the district to secure a $10 million U.S. Army Corps of Engineers grant to improve flood protection for a large swath of land generally west of Interstate 5 from Mossdale north to Weston Ranch and a large chunk of the developed portion of the City of Lathrop.

The initial work is already underway to build a series of berms next to 21 crucial spots in the levees. The 50-foot long by 4-foot high berms will serve to strengthen the levees if water manages to seep through.

The typical homeowner previously paid $1.75 to fund the Reclamation District. Passage of the ballot measure increased the tax by $5.60 to $7.35 for five years. The average assessment over five years would be just under $37.

Farmers previously paid 58 cents an acre. The five-year special assessment added $1.86 to that tax to push the cost to $2.44 per acre for five consecutive years.

River Islands at Lathrop has resolved their flood concerns by creating 300-foot wide levees.

The last floods were in 1997 when nine breaks along the San Joaquin and Stanislaus rivers ended up flooding 70 square miles, damaging more than 800 structures, forcing 4,000 people to flee, and ultimately caused $80 million worth of damages.

The biggest recorded flood in modern South County history started in 1950. It caused flooding west of present-day Interstate 5 in Lathrop. Flood waters threatened San Joaquin County Hospital and came within four miles of downtown Manteca. There were 2,000 people evacuated. Today, if the same flooding occurred, it would force 20,000 people to flee.

The Army Corps of Engineers spent $2 million to patch the existing levees after the 1997 flooding to restore them to the same condition they were in prior to the failure.

Protecting area southwest of Manteca

The large area southwest of Manteca that flooded in 1997 is not protected by Reclamation District 17 work. Instead, a separate district is moving forward with plans to upgrade levees along the Stanislaus and San Joaquin rivers in that area.

The City of Manteca is exploring the possibility of pursuing levee improvements as far south as Nile Garden School or extending the current levee that parallels Woodward Avenue west of Airport Way and extending it to a point about midway between Union Road and Tinnin Road.

The levee would be 80 feet wide and six feet high to the west of Airport Way, 50 feet wide and four feet high east of Airport Way, and 40 feet wide and four feet high east of Union Road.

Funding would come from property assessment plus development fees and possibly state funds.